Oscillating doctor knife bar and cutting angle adjustment



oct 28, 1958 A. M. FISCHER 2,857,612

OSCILLATING DOCTOR KNIFE BAR AND CUTTING ANGLE: AnJusTlmzm Filed March10, 1955 5 Sheets-Sheet 1 e W mw f ma U Y Maz/@ ATTORNEY Oct. 28, 1958A. M. FISCHER 2,857,512

' OSCILLATING DOCTOR KNIFE BAR AND CUTTING ANGLE ADJUSTMENT Filed Marchl0, 1955 5 Sheets-Sheet 2 INVENToR 2) wer/V, /avie BY MM; f m

ATTO R N EY A. M. FISCHER oscn. TING nocToR KNIFE BAR AND CUTTING ANGLEADJUSTMENT Oct. 28, 1958 5 sheets-sheet s Filed March 10, 1955 -mlhmwOct. 28, 1958 A. M. FISCHER 2,857,612

OSCILLATING DOCTOR KNIFE BAR AND CUTTING ANGLE ADJUSTMENT A Filed Marchl0, 1955 5 Sheets-Sheet 4 NVENTOR 4455er/Z /scf/fe ATTO R N EY Oct. 28,1958 A. M. FISCHER 2,857,612

oscILLATING DocToR KNIFE BAR AND CUTTING ANGLE ADJUSTMENT Filed Marchl0, 1955 5 Sheets-Sheet 5 l INVENTOR ATTO R N EY United States Patent 4OSCILLATING DOCTOR KNIFE BAR AND CUTTING ANGLE ADUSTMENT Albert M.Fischer, Dowagiac, Mich., assignor to Davenport Machine and FoundryCompany, Davenport, Iowa, a corporation of Iowa Application March 10,195s, semi No. 493,327

4'c1aims. (ci. 15-2565) The present invention relates to doctor knivesfor moving surfaces and is more particularly directed to an apparatusfor adjusting the cutting angle and depth of 'cut of oscillating doctorknives, and to a means for the simple accomplishment of coordinatedoscillation while the surface served is in motion.

The art has long recognized that present day doctorknife assemblies areinecient in their operation when the material per se is changed fromthose conditions for which the cutting angle of the knife assembly isinitially set or designed to operate under. In such instances where theoptimum cutting angle `must be determined by trial and error the dryerapparatus, for example, must be shut down while the cutting angle isbeing adjusted. Further, when the knife blade becomes dull most knownassemblies require the lengthy process of sharpening or honing or thereplacement of the dull blade. The cutting angle available for a singleassembly is limited by the inherent design features of the particulardoctor knife assembly. Therefore, as different materials are fed, thesebeing dictated by production pressures, the eiciency of the doctor knifemay be reduced because variations in cutting angle are not readilyavailable. Further, when the blade becomes worn, the thermal eihciencyof the dryer is reduced due to incomplete removal of material from thedrum and in instances of maladjustment scoring of the surfaces servedfrequently occurs. Present day known designs do not provide a structurecapable of prolonging the life of a blade by changing its cutting angleduring operation.

In order to reduce wear to a blade or damage to a surface due to unevenor excess pressures, present day construction of doctor knife apparatusgenerally has provided for an oscillating movement of the entire doctorknife assembly transverse the face of the drum paralleling the axis ofthe drum Where, for example, dryer drum surfaces are being served. Thatis to say in some designs the knife, the knife bar, the knife barsupport, the .support axles, the bearings, and even the bearing supportshave been designed to oscillate with the knife. Such a system has arelatively large power requirement. Minimization of these relativelylarge power requirements of drum and oscillating apparatus has long beensought. Further, the

equipment and mechanism for accomplishing such movement is expensive toproduce, install, maintain and repair. In such oscillating systems wherethe entire assembly oscillates the oscillation frequently damages thealignment of the equipment with which it is associated. No known doctorknives, either oscillating or stationary, have been designed to changethe cutting angle or angle of attack of the knife blade to a servedsurface, for example, a rotating drum, during continuous operation. Someadjustment of cutting or attack angle is required in all doctor knives,whether they serve a planal or cylindrical surface. In the previouslyknown doctor knives, the equipment must be stopped and the operationshut down in order to change the cutting angle of the blade. Since-knife a reduction of adjustments cannot be made during operation thethermal efliciency of the dryer surface is impaired and damage to thesurface served often results from unavoidable changes during service. Itwill be seen that the novel construction hereinafter described avoidsthese numerous diculties encountered by presently known doctoringknives.

Further deficiencies are found in, for example, double 'drum dryers ofthe present day construction, wherein end dams are utilized to maintainthe material within the confines of the working surface. These dams aremaintained in position by end dam pressure spindles. The pressure` ofthe spindles tends to force the dryer frames out of alignment and causedamage to bearings, knife bar bearings, et cetera. Spacers and bracingstructures are normally provided below the drum to prevent misalignment.These,

however, are not completely satisfactory. No known doc.

tor knife assemblies assist in providing bolstering support. Therefore,an object of the present invention is to pro vide an oscillating doctorknife assembly which will oscillate only the knife bar with the knifeblade.

continuous oscillation even during the changeV in cutting angles. l

A further object of the present invention is to provide an oscillatingdoctor knife which is adjustable in its angle of attack withoutinterruption of continuous operation.

A still further object of the present invention is to pro-A vide aneconomically fabricated doctor knife constructiom,

adaptable to a variety of planal or cylindrical surfaces and materials,which is easily maintained and repaireds, A further object is to providea doctor knife construc-y tion having as a result of reduced pressure ofthe doctor power requirement to the moving surfaces served.

Another object of the present invention is to provide a.` knife barassembly which will serve as a tie rod and assistY in counteracting theoutward thrust and stresses ofthe end dam pressure lspindles in, forexample, a single` or multiple drum dryer.

Another object is to provide a knife bar assembly which assures thermalefficiency of the surface served.

A still further object of the present invention is to pro-` vide anoscillating doctor knife which can be adjusted in cutting angle approachto present at all times a sharp, well-defined blade point to the servedsurface and thus prolo-ng the serviceabilityI of the blade, duringcontinuous operation of the knife assembly.

These and other objects will become apparentV to those skilled in theart as theV description of the present inven tion proceeds.

In the drawings:

Figure 1 is a front elevation of the oscillating knife'bar with cuttingangle adjustment and mounted over a served surface on a frame showncutaway.

Figure 2 is a cross section view taken on line II-II of Figure 1.

Figure 3 is a cross section view taken on line III--III of Figure 1.

Figure 4 is a cross section view taken on line `Iv-Iv et Figure 1.

Figure 5 is a cut away perspective detail showing theV mechanismpermitting oscillation to proceed while-ad? justments of the cutting-angle areV being made. Q

Figure 6 is a top plan view of double ydrtuudryei's andj a illustratinga` plural installation of doctor knife units in accord with the presentinvention showing the knife cases removed and indicating the ltie rodfunction of the doctor knifeiassembly- :Figure ,1-7 liis f.; a.schematic vrdiagram showing. a .blade @in contact withsa drum f surface.

v A4 E-igiire. is a schematicI diagram showing a worn blade. 2Eigure--9is.a schematicvdiagramshowing an adjusted worn blade.

. Figure 1.0j is .a schematic `diagram `demonstrating :the compound.adjustment possible in thestructure herein described` and showingthe.independent movements .that are coordinated to, givefvariations in -theangle of blade contact .,witlLa surface.V

,Eigu-re l1'` is,a,full. section ,elevation View showing the universalconnection shownin, Figure4.

GENERAL 'DESCRIPTION 'TVI-hepresent invention provides a:doctor knifeapparatus having concentric shafting,.and anV outer cylindrical caseforminga 4knifeabar. .The knifebar or outer cylindrical case Visdisplaced from concentricity ,with .the concentric shfting by a pairofeccentrics mounted on van outer or main shaft. The main yshaft has anoscillating drive shaft concentrically mounted within oneendvthereoftoprovide oscillating motion to the outer eccentrically rotatablemounted cylindrical case or knife bar. The linkage between `the-driveshaft and case through the` main shaft isaccongplished by a'drive pin.The cylindrical., case or knifejbarcarries a knife clamping plate and adoctor blade. Means associated with the outer eccentrically rotatablymounted `cylindrical..case or knife bar are provided to rotatel theblade carrying case about the eccentrics. Additional means are providedto rotate the .main shaft and associated eccentrics independently of anyrotation in the eccentrically vmounted cylindrical case.

'In the preferredembodiment of the present invention, when; forexample,V the surface served is a rotating drum, adoctor knife assemblyis provided offset from the drum faceland extending longitudinallyacross the convex face of the drum parallel to the axis of rotation ofthe drum. Thedoctor knife assembly or apparatus comprises a pairfdbearing mounts or bearing supports mounted on, or attached to, thehousing or dryer frame; bearings mounted in lthe bearing mounts; a mainshaft rotatably mounted Within'the bearings and extendingacross the faceof the drum parallel with the axis of rotation of the drum,at least aoneend--of the main shaft being tubular and concentrically-bored toreceiveand journal-an oscillating drive shaft; and the main shaft beinglongitudinally slotted near-theainner end of the concentric longitudinalbore to provide a pair ofguideways through the opposite walls ofthexmain'shaft; a Vdrive pin penetrating said drive shaft projectingoutwardly therefrom through the slots provided therein andl beyond theouter circumference of the-main shaft; agrooved receiving ring fixedagainst longitudinal movement'in :the cylindrical case being inclearance rela tionship around the main shaft and having the drive pinofathe id rive; shaft inserted in :the groove .of theA ringfor causing`axialxmovement-of the knife casein coordination with the oscillation ofthe drive shaft; anda pair Aof eccentrics keyed on the main shaft near:eacheen'd `rthereof forfmovementfwith the main. shaft between thebearings -of thefmain shaftaand; outboard of the longitudinalslotshinthe main shaft. Concentrically mounted over the keyed eccentricsA in"rotatable relation thereto is a cylindricalcase or knife bar tube havinga tangential external ledge 'for attachment ofta-.knifel clamp .plateand a 'doctorknife blade. Hubbed arms are adjustably secured to thecylindricalicasezor sleeveat eitherk end thereof, the armsubeingprovided with pivotal levers depending from the .hubsat either .end i ofthe doctor knifel assembly. `Shoulders integral .with-.the .cylindricalcase :inboard of.: saidhubs. and split rings .outboardof Asaid;hubsare,l providedtofmaintaimsaidhubfand associated arms ill/alignedaxial relation with said eccentrically mounted sleeve or knife bar.Independently adjustable means are provided on the end of each of thedepending arms for adjustably rotating the lever arms to cause resultingrotation of the cylindrical case or knife bar about the axis of theeccentrics.

. A bearing housing at one end gof the main shaft is pro- Y vided with aworm and Worm gear. The worm gear is keyed to the mainV shaft. A worm isprovided With'a hand SPECIFIC DESCRIPTION Referring with moreparticularity to the drawings a moving surface shown as a rotating drumdrycrllfris shown in Figure l having a drum 12 rotatable aboutan axis.In Figure 6 a double drum dryer 13 is illustrated. The axles 14 ofthedrums 15 are mounted,.in bearings` within a frame 16,having end ldams.17and 18. The end i dams 17 and 18 laterally confine the materialfedbetween the drums15 (Figure 6). VMounted on the frame 16 are a pairof bearing supports 19 and 20, respectively, each provided withbearingreceiving means.l i bearing support 19 and 2i) are bearings 22 and 23.One

of saidjbearing V supports .20 comprises a combination` bearing andWormgear housing 24. The purposelof the worm gear.` drive will be,morefully understood as- 1the l description proceeds.

AA main shaft .25 is rotatably mounted in the bearings.

19 and 20. On one end of the main'shaftV 25 and the worm gear housing24is keyed a worm 4gear26.V Each end of the main shaft 25 is securedoutboard ,of the bearing supports 19 and 20 thus preventingtheshaft fromshifting longitudinally. Various securingrmeans Amaybe employedythesimplest being split rings 27 and-28 re tained "in suitable grooves inthe main 'shaft 25. 'lhe wo-rmV gear end ofthe main shaft 25 is tubular,beingprovided with a concentricbore 29 extending longitudinallyf` into7the A.main shaft'25. Near' the extreme inner. Vendof.

the bore 29, the main'shaftZS is provided Witha pair of longitudinalslots 3i) and 31 through the Wall ofthe` mainfshaft 25 communicating themain shaft outer cir,- cumference with the concentric bore 29.

Concentrically mountedv within the bore 29 is an oscillating drive shaft32. The drive shaft 32 is reciprocatingly-ournaled in the bore 29. Atthe inner end33 of .the .drive-shaft 32' is a drive'pin34 securedthrough the drive shaft 32. The pin34 extends radially-outward from thedrive shaft V32 into and through the elongate slots 30 and 31 throughthe wall` of the'main shaft 25. The drive pin 34, attached to the driveshaft 32; can thus float-reciprocatingly in theslots Y3i) and 31. A

grooved receiving ring 35 receives the extensions of the y pin 34 whereit extends beyond the outer circumference of the main shaft25. The drivepin 34 rides in close tolerance inthe groove 36 of the receiving ring35- and the receiving ring 35 responds toany reciprocatory'movement ofthe drive shaft 372. of the. grooved receiver ring 35,- the -groove36 isdefined by the internal shoulder of the ring 35 and an abutting' annulus35a having any inside diameter smaller than the diameter of groove 36 soas to retain the drive pin 34in the groove 36. The receiving ring 35 isa hollow cylinder and is in clearance relationship with the main shaft25. The importance of this receiving ring 35 will 1become increasinglyapparent as the description proceeds;

.A pair of-eccentrics 37 and 38 are secured as by afkey 37a to thel mainshaft 25 inboard of the end dams17 '4 Within earch` In the preferredconstruction and 18 and outwardly of the slots 30 and 31 in the mainshaft 25. The eccentrics 37 and 38 are in fact cylinders having anoffsetaxis from the axis of the drive shaft 32.

A cylindrical case'or knife bar sleeve 39 is concentrically mounted onthe eccentrics 37 and 38 for rotatable movement thereover and in slidingreciprocating motion therealong. The cylindrical case 39 has atangential flanged ledge 40 for mounting a doctor knife blade 41 and adoctor clamp plate 42 thereon. The blade 41 is preferably secured by theclamp plate 42 and the thumb screws 43 are provided for alignment. Bolts44 through the ange 40 and the blade 41 draw the blade 41 securelyagainst a machined step 45 in the anged ledge or shoe 40. Thus, thecylindrical case or sleeve 39 is rotatable on the eccentrics 37 and 38and carries a blade mounting ledge 40 to which thte blade 41 isattached. On the inside of the cylindrical case 39 a shoulder 46 isprovided against which the receiver ring 35 is positioned. A spacedannular groove 47 is provided in the inside of the cylindrical case 39for accommodating a snapring 48 against which the other side of thereceiver ring 35 abuts. Thus, the cylindrical case 39 may be rotatedabout the receiver ring 35, but the case 39 is moved longitudinally asthe receiver ring 35 is oscillated by the drive pin 34 in response tolongitudinal movement of the drive shaft 25.

While the receiver ring 35 has been described as rotatable within theshoulder 46 and the snap-ring 48, it may also be held tightlytherebetween and prevented from movement independent thereof. Theannular receiving ring groove 36 thus becomes the surface within whichthe pin 34 rotates. The -reciprocation of the knife bar or case 39 stillis controlled by the reciprocation of the pin 34 with the drive shaft32.

At each end of the cylindrical case 39 are collar-like brackets or hubs49 and 50 rotatably and adjustably Vattached to the cylindrical case orknife bar 39. The adjustable attachment is accomplished by means of setpins 51 and 52, each having an eye 53 and 54 at their outer extremity."The brackets or hubs 49 and 50 accommodate the set pins 51 and 52 whichlock the brackets 49 and 50 in a desired position-on the ends of thecylindrical case 39. Clearance is provided between the brackets 49 and50 and the bearing supports 19 and 20 so that as the cylindrical case orknife bar 39 is oscillated the moving brackets 49 and 50 do not contactany part of the frame 16 or the bearing supports 19 and 20. Lateralmovement of the hubs 49 and 50 along the cylindrical case 39 isrestricted by annular shoulders 49a and 50a on the case 39 and splitrings 55 and 56 seated in annular grooves 57 and 58 in the surface ofthe case 39 near the ends of the case 39.

Arms 59 and 60 in the nature of levers depend from the brackets or hubs49 and 50. Knife pressure adjusting means 61 and 62 mechanically andlinkedly extend to adjustably engage the lever arms 59 and 60. Themovement of the adjusting screws 61 and 62 causes arcuate movement ofthe levers 59 and 60 and corresponding rotational movement of the case39.V The arms 59 and 60, in the nature of levers, are pivotal where theyattach to the brackets 49 and 50. By thus pivoting the arms 59 and 60rockably from the brackets 49 and 50, rotational adjustment of the case39 is provided and the pivoted arms 59 and 60 can clear any associatedapparatus in the manner of a pivotal link. The knife pressure adjustingscrews 61 and 62 are actuated by handwheels 63 and 64 rotatable infixedly mounted blocks 63a and 64a, correspondingly left and right asshown in Figure 4.

Internally threaded actuating members 65 and 66 are threaded onto theknife pressure adjusting screws 61 and 62, and are pivotally connectedto the depending ends of the arms v59 and 60 through unique pivotalblocks 67 and 68, respectively. Then blocks 67 and 68 are pivotallymounted at one end to the arms 59 and 60 and rotatably connected theretoin -the manner of a universal.

The rotatable connector is further right angularly and rotationallymounted in the pivot blocks 67 and 68 as clearly shown in Figure l. Themechanism shown in Figure 4 provides a suitable steady rest or guideagainst any objectionable rotational movement. Element 65 is shown as aninternally threaded sleeve having an outer sleeve 65a slidably mountedthereover said sleeve 65a having a cylindrical projection 65b extendingright angularly .therefrom journaling through arm 67. This novelarrangement provides a universal action maintaining each main part inproper alignment yet permitting angular movement of the parts. Thus arm59 can swing in an arc in response to lineal movement of block 65 alongscreen 61. The universal vcoupling provides in accordance with themechanical requirements of the respective member the movement ofinternally threaded members 67 and 68 along screw 61 and 62 permitting aswinging or arcing movement of arms 59 and 60 without binding members 67and 68 to screws 61 and 62 respectively.

Assuming the set pins 51 and 52 to be locked to the case 39, rotation ofthe handwheels 63 and 64 causes corresponding lateral movement in theactuating members 65 and 66 and through the linkage with the universaljoint arcuate movement of the arms 59 and 60. The arms 59 and 60 aremoved causing rotation of the brackets 49 and 50 land subsequentrotation of the case 39. The bearing housing 20 comprising one of thebearing supports has therein a worm 69. The worm 69 is in operableengagement with the worm gear 26. The worm gear 26 is keyed to the mainshaft 25. A worm handwheel 71 is operably attached to the shaft of worm69.

The housing 24 of the worm 69 and associated bearingsy 72, as necessary,are provided in the bearing support 24. As the worm 69 is rotated theworm gear 26 is actuated, thus rotating the main shaft 25 and theeccentrics 37 and 38 mounted thereon.

A reciprocating drive device 73 is provided outboard of the bearingsupport 20 and is directly connected to the drive shaft 32. Thereciprocating device 73 is aligned with the drive shaft 32. While thedrive device 73 illustrated, consisting of a fluid operated cylinder,represents one satisfactory means of accomplishing positivereciprocation of the drive shaft 32, other equivalent mechanicalexpedients wellknown in the art are intended to be descriptivelyincluded such as rack and pinion, hydraulic and pneumatic double actingpistons, and various cam, screw gearing and eccentric arrangements andreversible direct electric drives. In cooperation with the reciproeatingdrivedevice 73, timing means are intended to be included for varying thefrequency of oscillation as desired. The hydraulic lines 77 and 78supplying power to the drive device 73 are indicated in Figure l.

Operation In the operation of the oscillating knife bar and cuttingangle adjustment of the present invention, the worm handwheel 71 isrotated to adjust the cutting angle of the doctor knife blade 41 to thedesired angle for the particular material to be removed from thecylindrical or planal served surface 74. The worm handwheel 71 operatesthe Worm gear 26 which is keyed or otherwise secured to the main shaft25, thus rotating the main shaft 25. This rotation of the main shaft 25will vcause corresponding rotation of the keyed eccentrics 37 and 38.Rotation of the eccentrics 37 and 38 on the axis of the main shaft 25will change the angular relation between the main shaft 25 and thecylindrical case 39 carrying the knife blade 41. The angularrelationship as between blade 41 Vand served surface 74 will be alteredcorrespondingly but the action of the eccentrics 37 and 38 ispredominantly cam-like in nature serving to back ot from Aor approachthe blade 41 to the surface 74 served. The action of eccentrics eitherbacks off the blade 41 in relation to the surface served 74 or moves theblade 41 into closer relationship with the served surface 74. Position7' 'BfinlFigure 10 demonstratesgthis, adjustment .on au exaggerated'scale.

The set pin 51 or` S2 in one of the brackets '49-or 50 is withdrawn.`The other set pin 51 or 52 is left in vits locked'position in thecylindrical case 39 andthrough the'bracket-49 or 50. vThe screw -61 or62engaging the arm 59 orl 60 is rotatedby means of handwheel V63 or 64soas torotatethe cylindrical' case 39 by arcuatelymovingfthe-bracket49'or 50 which-is still locked Aintoengagementwwithxthe case 39. lThis movement pivots the case 39` and-'theassociated-knife blade 41- into or out of engagement-with thecylindrical or planal working surface andtthus changes the attack angleof the' blade V41 when coordinatedA withA the-action ofthe eccentrics 37and38. When 1drumdryers-15 are servedy'this compoundadjustment'gresultsinia variety of cutting angles being made availableat -the'drumsurface. 'T he pressure of the blade 41 on rthe 4surface iscontrolled `primarily by 'the rotation of the case"39^andtheseadjustments are made without interruption'of movementin the drumdryers or `the reciprocation-of 'the blade :41. The other handwheel 63or 64 is then Vrotated in the same direction until 'its set pin`-51 or'52 which was withdrawn drops Vinto a' hole 75 or76 provided inthe caseor knife bar'39. The set pin'holes'75 and"76-are `in alignment tothatthe motion in both screws is thus coordinated. From this positionthe handwheels V63 and-64 krotating `the case`39are Vused to regulatethe pressure forcingftheyknife blade 41 vagainst the drum surface'74.

The reciprocating drive device 73 is energized causing reciprocation ofYthedrive shaft 32. .Thefrequencyeof oscillation is adjusted as 'desiredVby timing means not illustrated. This recipro-cationof the Adriveshaft32 and its associated drive j-pin 34 causes correspondinglongitudinaland axially oscillatory movement ofthe' cylindrical case 39and its `associated blade 41. This'reciprocating-linkage is acomplishedthrough the drive pin 34 reciprocating inthe slots `30 and311through'themain shaft ry andthe connection, ofV the drive pin 34 in`the groove 36 of", the longitudinally xed receiving ring35. The Adrum12y (where the surface doctored is cylindrical) is nowgrotated anda^slurry is fed, forrexample, tothe dryer.

If it isidesired to change the cuttingl angle of the blade 41 duringoperation, it is necessaryto operate the handwheel'71 to cause eccentricblade displacement and coustant surface contact while simultaneouslyoperating handwheels`63 and 64 to revolve lthe case 39 and associatedblade 41 ongthel eccentrics '37 and 38, as indi-cated, tomaintaincontact pressure. It willbe understood that though manualmeansfor this adjustment have been speficially described automatic adjustment`as by springs, hydraulic, or electrical actuationtnay be insertedwithout a departure from my structure.

lnFigures'v7,.8, 9, and l0 the eect of the blade adjusting structure onthe blade .41 is indicated. In Figure 7 the blade 41`is shownrin angularpoint contact with a cylindrical drumsurface 74. The line X-X is atangent ,to the surface atthe point of blade contact. The lower .side ofthe blade Y-Y' establishes an intersecting plane through the point. InFigure, 8. an exaggerated view of a worn blade 41 is shown engaged withthe surface 74 of the drum 12. The wearing of the blade has created anew surface' W-W and the point of contact of the .blade has ybeendestroyed. ,InVFigure 9 it is seen that by increasing the originalcutting angle a new edge at the point of contact ,with the drum has beenestablished as between the wear plane W-'W andthe plane X-X' tangentialto the cylindricalV drum surface 74 through the point. Such adjustmentsas these necessitate only a slight change of the cuttingangle and areaccomplished, with the herein described .structure .without .operationalinterruption. Movement of `the eccentrics 37 and 38 by turning the wormAhandwliejel7.1, while the structure isstill reciprocating, accomplishes'the changes'indicated with a minimum amountofinconvenienee. Asshown'in'Figure ljthe individual' 'movements comprising vthe compoundmovement of a"gblade41'areindicated by the phantom line exaggeratedVpositions aandb.

'Ini'Figure 6 a double'jdrum 'dryer y13 is shown-toillustrate `-adouble'drum installationl of a doctor `knife in'accord witl'x'the'present invention. -Various` plural installationsware encompassed inthe scope -of thef-described structure. 'With particular reference -to:the

doubleL drum'installation (Figure 6)fit willV be seen that` the doctorknife assemblies ,compriseeifective-tie rods rendering-theentirestructure more rigid despite the i constantoscillation of the `blade 41.`VThe'tie-rod effectl of the described doctorgknife assembly alsocounteljacts` the pressur es ontheA end damsl 17 and 18 rtending' tospread Vthel frameil.

It willbe seen that'the'change loftangle can'bemade. withoutstopping-the vdrumy or the oscillating'knife bar.

Similarly, depth 'of cut is, where desired, independently changedwithout interrupting continuous process operation. The advantages of;such anl operation are ap-3 cl'rocolate.;pulp,V or `plastic orsemi-plastic vmaterialien planar or4 cylindrical'stabilized surfaces.vIn .association with continuous yeastfdryingequipment of all knowntypes the apparatus described has proved itself to be unusuallyeflicient in minimizing power v,requirements and avoiding process`interruption.

[It is -thus seen that-,a novel and 'highlyl useful-arrangement has'been provided which will allow rdeptheand; cutting -angle adjustmentgofthe doctor `blade during p operationand al novel system-has beenprovided-toA continuously oscillatejthe doctor blade. The apparatus hasproved 4economical to fabricate, -1 simple-- to i installand easy4 tomaintain.

It willqbe understood Athat-.various modifications of my describedyinvention may -bemade and such-modificationsgare -intended to beincludedvinthe scopeof my hereinafter appended claims, unlessthe -scope of'such,

claims negativesAV such inclusion.

Havingg'thus'describedj-my invention, -I/claim:

1.1m a doctor knife wasserriblyg-.the -combinationl in'- cluding: a-main `shaft -paralleling and f ois'et =from-`a served surface, journalmeans -'supper-ting said LAmain shaft; rcylindrical veccentric@members loperably secured to said main :shaft-in aligned-spaced relation.'thereon; a cylindrical case-'rotatablymounted over said-.eccentricmembers; means-within said case securing -said-.. shaft to said'casefor`axial-movement therewith; means'for selectively rotating said `shaft onits Vaxisgl-and ai knife support'rigidly longitudinally -andsubstantiallytangentiallymounted-fon said'cylindrical case and having-=asurface engaging bladeyattached thereto.

2. In a"doctorlknife-assemblyforserving-Ua #moving surface, thecombinationincluding: a--main-shaft'paralleling andeoifsetf-from-aserved surface, saidfmain shaft Ahaving a ,concentric longitudinalboreextending from one end-'thereof' and terminating `in.v a-radiallongitudinal `s lotted guideway through 'the wally of saidmain shaft;ljournal -means supporting said :main shaft; va

grooved -receiving -ring -mounted over-said -Inainl shaftl having acircurnferential keyway within-#the inner sur-` face thereofyaldriveshaftjournaled Within: the longitudinal-bore of, said main shaft;a-drivejpin-insertable. through sraidjmain shaft-guidewayandjengageablewith` said circumferentially groovedreceiving ring andsaid drive pin being attached to saiddrive shaft;-a cylindrical caseover said main shaft; and a reciprocating drive axially oscillating saiddrive shaft and said cylindrical case.

3. In a doctor knife assembly for serving a moving surface, thecombination including: a main shaft par alleling and offset from aserved surface, said main shaft having a concentric longitudinal boreextending from one end thereof and terminating in a slotted guidewaythrough the wall of said main shaft; journal means supporting said mainshaft; cylindrical eccentric members operably secured to said main shaftin spaced relation thereon; a cylindrical case rotatably mounted oversaid eccentric members; a grooved receiving ring xed to said case andhaving the groove thereof in cooperating alignment with the slottedguideway of said main shaft; a drive shaft journaled within thelongitudinal bore of said main shaft, said drive shaft having aprojection insertable through said main shaft guideway and engageablewith said grooved receiving ring; eccentric adjustment means keyed tosaid main shaft; rotating means adjustably secured to said cylindricalcase; a reciprocating drive operably secured to said drive shaft; and aknife support rigidly and substantially tangentially mounted on saidcylindrical case having a surface engaging blade attached thereto.

4. In an oscillating doctor knife apparatus, for adjusting a doctorblade to a served surface independently from the motion of such surfaceand the oscillation of such blade, the combination including: bearingsupports; a partially tubular main shaft in said bearing supports inparallel relation with a served surface and having a longitudinal slotthrough the tubular Wall portion; a drive shaft journaled concentricallyin the tubular portion of said main shaft; a pair of eccentrics keyed tosaid main shaft in spaced relationship; a cylindrical case in closetolerance rotational engagement over said eccentrics and carrying akknife blade; a grooved receiv ing ring in said case retained by saidcase from longitudinal movement; a drive pin projecting from said driveshaft through the slot in said main shaft and engaged in the groove ofsaid receiver ring; geared means for rotating the said main shaft andsaid eccentrics; collarlike brackets lockably engaging the ends of saidcylindrical case; lever arms depending from said brackets; actuatingmeans for arcuately moving said lever arms thereby rotating saidcylindrical case; set pins locking said brackets to said cylindricalcase; and a reciprocating device longitudinally oscillating said driveshaft and said case.

Bouda June 18, 1929 Hornbostel May 17, 1949

